Why the Speed of Light May Make it Impossible for Aliens to Ever Truly Visit Us

Why the Speed of Light May Make it Impossible for Aliens to Ever Truly Visit Us

shutterstock 99828914.jpg

Here's a Point to Ponder:  There are serious implications related to traveling close to the speed of light as it relates to the passage of time.  Would you be willing to take a 12 year trip to a distant star if it meant 100,000 years would pass on Earth - or more?


It's fun for an amateur astronomer to look at the stars and wonder, "What if?"  What if and when will we travel to the stars?  The answer is maybe never for some very good reasons.


Many of the stars we observe are hundreds if not thousands or millions of light-years away.  Light travels at 186,000 miles per second.  That's almost 300,000 kilometers per second.  That's fast, but you can't go any faster.  In fact, according to both Einstein and Stephen Hawking the speed of light is the maximum speed limit in our universe.  But what if we could approach the speed of light and travel to a not so distant star such as Alpha Centauri.

shutterstock 2262488.jpg


For the record, Alpha Centauri is 4.37 light years from Earth and is actually a  star system.  It has been acknowledged as the closest star system to our solar system, so it seems like a logical destination.  But there's a problem that any alien visitor would have experienced. 


The fundamental problem has to do with how time behaves when subject to two conditions:  speed and gravity.


According to Special Relativity Theory you can not exceed the speed of light.  However, you can approach it.  That's good, but there's a bigger problem.  The faster you travel the more time slows down around you.  This defines the fundamental idea that Hawking has proposed that time-travel is possible, but only into the future.


Get the book here.

“A possible way to explain the absence of visitors from the future would be to say that the past is fixed because we have observed it and seen that it does not have the kind of warping needed to allow travel back from the future.  On the other hand, the future is unknown and open, so it might well have the curvature required.  That would mean that any time travel would be confined to the future."


                                                            -Stephen Hawking 1988  

                                                            A Brief History of Time


Let's look at it from a functional approach.  Alpha Centauri is the closest star system to our solar system.  If we had a vehicle that could approach the speed of light (186,000 miles per second) we could probably do the trip in 12 years.  This would include a ramp-up to about 180,000 miles per second (less than 186,000) over the course of a year, a cruise for about 3 years, and a gradual braking for about a year.

Artist’s impression of the planet around Alpha Centauri B (Annotated).jpg


Once we enter this new solar system we might want to explore for a couple of years and then ramp-up and return.  The total roundtrip would take us about 12 years before our triumphal return to Earth. 


But that's where we confront the dilemma.  According to special relativity theory our speed has caused time to slow down for us, while it has accelerated around us.  When we return to Earth it's possible that thousands if not millions of years have passed (Edit: This assumes the whole trip took 12 years onboard the ship and not 12 years from the point of view of planet Earth. Maybe somebody could do the exact maths on the time dilation for us).  Will anyone be here to welcome us home?  Or worse, will the planet still exist?


And what if there are intelligent beings with advanced technology that can, or have visited our planet?  Unfortunately, some basic concepts related to our quantum universe and verified by Albert Einstein and Stephen Hawking make this possibility equally problematic.  What applies to us, applies to all and aliens would be subject to the same rules related to speed, time-travel and the one-way trip few of us would want to make. 



The talking point is that any trip of significant distance at close to the speed of light is a one-way trip.  How many of us want to make that trip, and more to the point, how many aliens would be willing to make the same sacrifice?   If any do they would probably want to stay a while because they have nowhere to "go home." 


The counter argument is something called "warp-theory."  It's the idea that if you can bend the fabric of space you could travel at close to the speed of light, without exceeding it, and bend space to get you to your destination more quickly. Here is an interesting video on warp drives.


That's fine if you're in a hurry, but wait a minute - you were traveling at close to the speed of light to get there.  Uh oh.  Special relativity theory applies and time will still have traveled slower for you.  Even travel at warp-speed could subject you to the time-dilemma of special relativity theory. 


So what's the solution?  Simple.  Stay in your backyard with your family or friends and watch the stars and wonder.  Unless you're ready to leave them and all of humanity behind forever it's not worth the trip. 

Find more on: Astronomy Science and News

Back to Learn Astronomy

If you enjoyed this, sign up for the newsletter

 Privacy policy and cookies | Disclaimer | Contact Us | Credits | Resources | Site Map © LearnAstronomyHQ.com 2012-2014